Method of uniting iron or steel with each other and with other metals.



UNIT D STATES PATENT OFFICE.

EVAN IiLEWELYN DAVIES AND WILLIAMGJCLARKj, or wEssELs NEK, NATAL.

METHOD OF UNITIN'G IRON OR; STEEL WITH EACH OTHER AND WITH OTHER METALS.

Application filed August 7, 1905' Serial No. 273,212.

Specification of Letters Batent.

Patented April 21, 1908.

with Other Metals, of which the following ishis invention'which is animprovement on the method described in the specifications to Britishatent No. 10763 of 1899,rela'tes 5 to a method of welding iron or steelwith each other or with other metals such as copper or its alloys,silver or gold or their alloys,. and

to the composition of fluxes to be employed in connection with suchprocesses, the object of the invention being to obtain a more com,-plete adhesion of the metals to one another j than has so far beenaccomplished.

The improved method will be with reference to the coating or welding ofsteel sheets with a film or coating of cop er of any desired thickness,but it is to be un er: stood that it may also be applied to the coatingof any kind of iron p ate, tube or wire with other metals than copper orwith cop' per or other alloys,- and also to the uniting of iron or steelplates .or barawith each otheror with plates or bars of copper or othermetal or alloy.-- I The iron or steel plate to be coated is heated to atemperature, which should be considerably above that of the meltingpoint of the coating metal, and when possible approximately that oftheboilin'g point of t e coating metal, such a temperature under usualconditions entailing the. conversion of any iron oxids on its surfaceinto the black oxid, and is laced in a suitable mold in a furnace in wich itis maintained at-about the same temperature. In this furnace, in

the melted condition sup lies of a flux, the

composition of which wi be hereinafter de-v scribed, and of copper orother coating metal.

flux, preferably covered with'a layer-of cardescribed suitably formedhearths, there are kept in he mold containing the iron plate is thenpartly filled with liquid,

bon in suitable form, such as ground charcoal, the iron oxid on theplate combining with fluxand leaving a'clean iron surface.

The separation of the iron oxid and its chemical combination With theflux may be. facilitated by .the use of scrapers or rakes passed overthe surface of the iron plate and agitating the flux. The melted copperis then admitted to the mold and being heavier 5 than the" flux takesits placeyso that the liquid copper becomes covered with the-layer offlux thus reventing to some extent the oxidation of its surface whenexposed to an oxidizing atmosphere. -The. me ted copper 7 is thusbrought into intimate contact with a clean iron surface at a weldingheat, and an intimate union of the copper and iron is obtained,thisbeing'facilitated and a homogeneous distribution effected by theuseof scrapers or rakes as above described, or by' other suitable meansof agitating the layer of melted copper. The mold containing'the coatedplate u on its withdrawal from the furnace may e covered with a sheet ofso metal to revent access of the air as far as possible uring cooling. 1Since'it is practically impossible in carrying out the process in afurnace with an oxidizing atmosphere to prevent the oxidation 5 of thecopper to some extent, it is important that the copper used should bewhat is known asslightly over oled, or in that condition of brittlenesswhic requires oxidation to bring it back to the tough condition. Shouldthe heating furnace used not have an oxidizing atmosphere it may beunnecessary to use over poled'copper;

When it is deslred to coat both surfaces of the late, it is practicallynecessary to use two urnaces, inone of which copper is kept molten in abath having a magnesite or other basic lining, while the other furnaceis used to raise the plate "to the temperature fofthe molten copper orsuch a higher tem erature as may be necessary to allow fort e una-vvoidable fall of temperature in bringing the late and the molten copperinto contact. his latter furnace also contains on its hearth a bath ofthe particular flux used in the procass in a molten condition,- and the"late on being taken from the furnace is st immersed in this bathwhereby its surface is cleaned and covered with a film or molten fiux,and is then placed in a suitable mold of 1 0 ma esite" clay or ordinaryfoundry loam, whichhas been previously heated to as high a temperatureas it standby a gas flame" or other suitable means. The molten copper isthen run into the mold and, displacing the film of flux comes intointimate contact with the clean'surface of the iron at a welding heat'and rigidly adheres thereto.

In a modified method of carrying out the 'process and one which obviatesthe difficulty experienced by the fact thatthe liquid cop- 1 its edge 'wper more or less readilypermeates the lining of the copper bath hearth,more particularly if ordinary silica bricks are used for this purpose,the plate to be coated is formed with ich may previously have beenreduced in thickness, u wardly turned, preferably through an ang e of 90at least, and

- liquid or solid flux is poured or sprinkled over the surface to becoated and the coating metal is added in the molten condition or insmall ieces distributed over the surface, no mold eing required.Suflicient flux ShOUld be added to cover completely the copper or othercoating metal when melted and the copper used should be over poled ifthe furn'ace to be used has an oxidizing atmosphere:

The flux and copper are melted in heating the plate as rapidly aspossible to an oxidizing temperature, which may be done in any' amountto 4 per cent. or thereby of the total quantity of flux, of sodiumphosphate or bone ash, the phos horus serving to increase the fluidityo' the copper, and thus preventing pin holes. At the same time theproportions and even the constituents may vary, as for example by theomission of the sodium borate or the substitution for the carbonate andborate of soda of other carbonates and borates and the proportions givenabove are by no meansthe on y proportions which may give good results,such variations deending upon the character of the metals to lie weldedand the composition of the lining of the flux bath if such is used. Thesilica and carbonate of soda by themselves form a, fusible silicatewhich has the property at the worklng temperature of dissolving the ironoxid and the sodium borate is added chiefly for the purpose ofdissolving any copper oxid which may be formed, or in conjunction withcarbon which is added to the flux elements, preferably in the form ofground charcoal, to reduce or to prevent the formation of such, therebyreducing waste of copper.

When wire or thin strip metal is to be coated this is heated to anoxidizing tem-' perature and then drawn through a vessel having asuitable neutral or basic brick lining containing the molten copper anddivided into two parts by a depending partition which, however, does notextend to the bottom of the vessel, so that the wire or strip can bedrawn through the molten metal under the partition. On the entering sidefor the wire or strip, the surface of the cop )er is covered with aflux, such as described a ove, which is in the liquid state, while onthe emerging side of the vessel, the flux covering consists usually ofsodium carbonate and sodium borate with the addition of powdered carbon,but the composition of this flux may vary in accordance with theconstitution of the lining of the containing vessel, the only conditionto befulfilled being that the surface of'the copper bath will beprotected from oxidation. On passing out of the furnace the wire orstrip may be cooled by passing through a stream of water and afterwardsannealed or otherwise treated as may be desired.

When tubes are to be coated these may be treated in a similar vessel thetubes being caused to enter the vessel transversely and to revolve byrunning down an incline. Or two or more vessels may be used, the firstof which contains molten flux in which the tube is first immersed, thesecond bath containing the molten coating metal and being situated at alower level at the end of an incline down which the tube rolls from theflux bath, while thethird bath, if such is used, is at'a still lowerlevel and contains molten flux of a similar nature to that in the firstbath. The tube continues to roll through the molten metal in the secondbath in which it is par-' tially immersed and becomes uniformly coatedtherewith, and fromwhich it passes or. is transferred to the third bathin which it is temporarily immersed for the removal of dirt from themetal surface.

The rolling of the tube is maintained by means of an inclined plane orotherwise after it leaves the bath until the coating metal has becomesolidified. When coating iron or steel withgold or silver or alloysthereof or ofcopper, the same fluxes are employed but the proportionsmay be somewhat varied to suitthe temperatures re uired for the variouscoating materials, tie essential condition being that the flux is in afluid condition at the welding temperature.

If the plate or other article to be coated is rusted or itted it isadvisable before treating it asiiereinbefore described to dissolve therust by treating with suitable acid and to remove the inequalities ifany by rolling or other suitable means so as to obtain a smooth surface.

When it is desired to weld iron or steel with themselves or each otheras for. example to weld hard tool steel on a mild steel bar, the

parts to be welded are raised to the oxidizing temperature of iron andare then lungedv into a bath of flux maintained at t e' same temperatureand containing silica and car bonate of lime in about e ual proportions.The'fiux dissolves any ox i on the surfaces to be welded, which byimmersion in the flux are brought to -a white heat, thus enabling thewelding to be effected on bringing the two steel bars together quicklyon Withdrawal in the ordinary way.

We claim:

1. The herein described method of uniting iron or steel with each otheror with copper gold or silver or their alloys which consists in heatingthe surface of the iron or steel considerably above the melting point ofthe metal with which it is to be united,-ren1oving the iron oxid bya-suitable flux andbringing' the uniting metal heated to a correspondingtemperature into intimate centac't with the surface of the iron whilethe temperature is maintained, substantially as described.

2. The herein described method of uniting iron or steel with each otheror with copper goldor silver of their alloys which consists in heatingthe surface of'the iron or steel considerably above the melting point ofthe metal with which it is to be united, immersing the iron or steelsurface in a suitable flux to remove the oxid, and displacing the fluxfrom the iron or steel surface by bringing the latter into intimatecontact with the metal with which it is to be .united in a mold, thetemperature of the mold and of the said metal having beenpreviously-raised tov a temperature considerably above the melting pointof said metal, substantially as described.

I 3. The hereindescribed method of uniting.

iron or steel-plates with copper, gold or silver or their alloys whichconsists-in 'heatin the iron or steel considerably above the me tingpoint of the metal with which it is to be united and in removing theiron oxid by a suitable flux and bringing the metal with whichit is tobe united into intimate contact with-the iron by adding the said fluxand metal, thelatter in small pieces to a mold formed by upturning theedges of the plate, while the 'tem' perature of the latter ismaintained, substantially as described.

4. The herein dGSCI'll'X-Ml method of uniting iron or steel witheachother or with copper,

'ate'and 'a small quantity of sodium goldor silver or their alloys,which consists in heating the surface of the iron or steel approximatelyto the boiling point of the meta with which it is to be united, removingthe iron "oxid by a flux containing approximately equal quantities ofsilica and an alkali carbonate and a small uantity of sodium phosphate,and heating t e metal with which the iron or steel is to be united to acorresponding temperature and bringing the metal into intimate contactwith the surface'of such iron or steel while the temperature ismaintained,

substantially .as described.

5. The herein described method of uniting iron or steel with each otheror with copper,

gold or silver or their alloys, which consists in heating the surface ofthe iron or steel approximately to the boiling point of the metal withwhich it is to be united, removing the iron oxid by a flux containingapproximately equal quantities of silica and sodium carliIon osphate,and'heating the metal with whic the lIOIl or steel is be united to acorresponding temperature and brin ing the metal into intimate contactwith t e surface of-such iron or steel while the temperature ismaintained, substantially as described.

6, The herein describedmethod ofuniting iron or 'steelwith each other orwith copper,

gold, or silver or their alloys, which consists in heating the surfaceof the iron or steel approximately to the boiling point of the metalwith which it is to be united, removing the ironoxid by a fluxconsisting of silica, sodium carbonate, and sodium borate in about equalproportions with the addition of a small quantity of sodium phosphate,and heating the metal with which the lI'OIl or steel is to be unitedto-a corresponding temperature and bringing the metal into intimatecontactwith the surface of such iron or steel while the temperature ismaintained, substantially as descr bed. i

In testimony whereof we have signed our names to this specificationinthe presence of two subscribing Witnesses.

.E. LLEWELYN DAVIES. W. CLARK.

Witnesses: i

,C. 'L. HoPKms,

JosEPH WILLARD.

